Liquid heater



June 25, B MA 1,718,866

LIQUID HEATER Filed June 11, 1928 INVENTOR @uwnQ/W BY M da ATTORNEYPatented June 25, 1929.

UNITED STATES BARNETT W. MACY, 0F JACKSONVILLE, FLORIDA. i

LIQUID HEATER.

Application filed June 11,

This invention relates to improvements in liquid heaters, and itconsists of the constructions, combinations and arrangements hereindescribed and claimed.

An object of the invention is to provide a heater in which hot waterwill be stored for use when required, the heating of the water beingdone by an electrical unit which is subject to the control of a heatedcolumn of oil, the opening and closing of a thermostat and of anelectrical circuit associated there- .with, being directly dependentupon the temperature of said column of oil.

Another object of the invention is to provide a special provision for afurther opening of the electrical circuit in case the current should beturned on while the storage tank is dry,.this provision relating to theheated column of oil, mentioned before, and

to the particular disposition of a control tube in which the thermostatis located.

Other objects and advantages appear in the following specification,reference being had to the accompanying drawing in which Figure 1 is acentral vertical section of the improved water heater,

Figure 2 is a sectional view of the heating unit, port-ions being shownin elevation, Figure 3 is a cross section taken on the line 33 of Figure2.

The invention disclosed in this application is an improvement on theliquid heater disclosed in application No. 3, Serial No. 282,530, filedJune 4, 1928 by Barnett \V. Macy, one of the features being a branch ofthe heater tube that contains the thermostat, said branch being locatedmedially of the heater tube so that a close regulation of thetemperature of the volume of'water in the reservoir may be obtainedwithin approximately five degrees. A feature incidental to theconstruction is the disposition of the thermostat in the outer end ofsaid branch at a point outside of the heater, the thermostat thereforbeing accessible so that any necessary repair or replacement may readilybe made without dismemhering the heating unit.

A tank 1, of any suitable type, provides a reservoir in which hot wateris to be stored in readiness for use. To that end the tank may be madeas large or as small as specific requirements may demand. The tank has aheavy sheathing of insulation 2, this sheathing being held in place byan outside jacket 3. A pipe or tube 4. is introduced into the sealedclosure 5.

1928. Serial No. 284,534.

3. The tube 4 may be, and preferably is,

welded to the tank 1 as the place where it enters the top, so that thetube 4 is prac 'tically a part of the storage tank.

The tube 4 extends to a point close to the bottom of the tank 1 wherethe end has a The tube contains oil which assumes a level above theorifice of a control tube 6. This tube is smaller in diameter than theheater tube 4. It extends at right angles to the tube 4, although thereis no restriction on the particular disposition of the control tube, andinasmuch as the control tube is a branch of the heater tube it followsthat it contains oil and that a thermostat 7 located in the controltube, is always immersed in oil. The thermostat maybe of any knownconstruction.

Particular attention is directed to the fact that the control tube 6 islocated medially of the heater tube 4. By so locating the control tube acloser regulation of the heating of the volume of water is obtained. The

scription of the operation. Location of the control tube elsewhere wouldnot have the same effect, and the regulation of the heating of the waterwould be erratic. The control tube has two special functions, first: asan automatic regulator when. the tank 1 is full of water and, second: asa safety device in case the current is turned on when the tank is empty.

The heating unit, to which allusion has been made, is constructed asfollows: a base plate 8 provides a top closure for the tube 4: as wellas the sole support of the heating unit. Two terminal rods 9 and 10extend from the base plate to a point of connection with a top spacerbar 11 of insulating material. Resistance wires .12 are threaded throughholes in the bar 11, as well as Ehr'ough holes in a bottom insulatingspacer Bushings 14 and 15 insulate the rods 9 and 10 from the plate 8.The latter also provides the base from which a'stud 16 depends. Thisstud passes through the plate 8 and the bars 11 and 13, the exposed endsbeing threaded to receive nuts 17 that hold the assembly together. Thestud passes through upper and lower porcelain or other insulatingsleeves l8 and 19 which serve to fii' the positions of the bars 11 and13. A conreason for this is fully explained in the denector 2O suitably.carried b the lower sleeve 19, has screws 21 at whic 1 the ends of theresistance wires 12 are joined so as to complete a part of. the-circuit.

Insulating twine 22 is used to tie. the resistance wires 12 to thecentral insulating tube 19, the purpose being to hold the wire firmly inplace and prevent it from sagging out of position. Threads 23 permitscrewing the tube 4 into a connection ring 24. The plate 8 istemporarily attached to the ring 24 by machine screws 25. A knock outbox 26 forms the upper terminal of the heating unit. It is here that thenecessary connections with the rods 9 and 10 are 111a( i e. A conduit 27joins the box 26'With'a control box 28 from which the thermostat isaccessible. This control box will contain a switch S by which thecurrent.

is turned on and off. A suitable drain 29 provides for emptying. thetank. Cold water is introduced at a pipe 30 and hot water may flow outof a pipe 31".

The operation is readily understood. .As has been emphasized already,the medial location of the control tube 6 in reference to the heatertube 4 is one of the important features. Assume, first, the caseof afull tank of cold water. 1

The thermostat setting is for 145 degrees (for example). Upon turningthe current on at the switch S the effect of the electrical unit will beto heat the column of oil in the tube 4. The heat naturally rises sothat the volume of water in the tank 1 begins heating at the top.

The heated zone extends downwardly until it reachesand passes thecontrol tube 6. By the time that the water at the bottom of the tank 1becomes preceptibly warm, the water surrounding the tube 6 will reach atemperature approximate the setting of the thermostat. It is then thatthe oil in the control tube 6 reaches the temperature at which thethermostat *3 will be operated thus opening the circuit and temporarilysuspending the action of the heating unit;

At this point a further explanation must be made before the function ofthe control tube 6 is described as a safety device. The oil in. the tube6 does not become heated. to the temperature of the column of oil in thetube 1 by the heating action of the resistance element, as might besupposed. The resistance element will heat the column of oil, and theheat units will assemble in the tube, but will not traverse the lateralcolumn of oil in the tube lltis not until the water becomes sulhcicntlyheated that heat is conducted to the lateral column of oil in the tube6, and when suiiicicnt heat has been so conducted to the lateral oilcolumn then the thermostat acts as already stated.

In other words, the lateral oil column in the tube 8 and the thermostat7 operate by misses indirection. The principle is this: The verticalcolumn of oil in the tube 4 is subject to becoming initially heated,always exceeding the temperature of the volume of water, but thetemperature of the lateral column of oil in the control tube 6 is alwaysthe same as the temperature of the water surrounding the tube. A livedegree drop in the surrounding temperature and of the lateral column ofoil will serve to permit the thermostat to again cl5se and start theheating operation.

Assume, next, a condition in which the tank 1 is empty and the currentis inadvertently turned on. It is now that the con-' trol tube 6 acts asa safety device for, were it not for the function of the control tube atthis time, the electrical heating unit would burn out. The verticalcolumn of oil will heat rapidly, and as the zone of heat travelsdownwardly it will reach the control tube (Sand heat the lateral columnof oil, there being no surrounding medium totake the heat away.

The heating of the lateral column will soon become so great as tooperate the thermostat? The opening of the circuit will follow.

It has been stated that the location of the control tube 6 at any pointother than stated would not have the same effect. For instance, if thetube 6 were located farther down, the water for the top of the tank 1would be converted into steam long before the zone of heated waterextended down far enough to reach the control tube and cause thenecessary operation of the thermostate 7 to alleviate the undesiredcondition.v Conversely, if the control tube were located farther up, thethermostat would have to be 1 be at steam temperature, while the Waterbelow would be cold. Any disposition of the control tube ti below themedial position would require successively lower settings of thethermostat to eliminate excessive temperatures at the top. An obviousresult would he that the temperature of the water Wouldhave to takeperceptible drop before the thermostat would act to again start theheating operation. There is a lilielihood theta person drawing off waterwould get cold water, rather than hot water as desired.

llv'ith the control. tube 6 located in the medial-position, there willbe an assurance of an ample quantity water in the tank 1 at atemperature of 1&5 degrees or thereabout.

will immediately 1 to act in the While the construction and arrangementof the improved liquid heater is that of a generally preferred form,obviously modifications and changes may be made without departing fromthe @spirit of the invention or the scope of the claims.

1. A heater comprising a tank adapted to contain a substance to beheated, an electrical heating unit to impart heat to said substance, athermostat to control an electrical I circuit in which the unit issituated, and a confined volume of liquid in which said unit andthermostat are immersed, said volume of liquid being subject to a rapidincrease in heat in the absence from the tank, of said substance to takethe heat away, for an operation of the thermostat to open said circuit.

2. A heater comprising a heating unit, control means by which theheating effect of the unit is controlled so that it is renderedoperative and inoperative, and a fluid containing said unit and fromwhich heat is directly imparted to a surrounding medium to be heated, ina portion of which fluid the control means is immersed, depending uponan equalization of the temperature of said fluid portion and said mediumfor its action on the control means.

3. A heater comprising a heating unit, control means by which theheating eflect of the unit is controlled so that it'is renderedoperative andinoperative, means containing a column of oil in which theheating unit is immersed, being subject to being heated and to impartheat to a medium surrounding said means, and a branch in which saidcontrol means is situated, being in communication with said oilcontaining means so that the control means is immersed in the oil.

4. A heater comprising a heating unit,

' control means by which the heating effect of the unit is controlled sothat it is rendered operative and inoperative, a heater tube containinga column of oil in which the heating unit is immersed and which oilimparts heat to a liquid medium surrounding the tube, and acontrol tubein which the control means is situated, being in communication with theheater tube and containing some of the oil in which the control meansisimmersed, but remaining relatively cool until the heat zone of saidmedium reaches the control tube so that an equalization of temperaturesof the oil in said tube and the surrounding medium is established.

5. A heater comprising aheating unit, control means by which the heatingeffect of the unit is controlled so that it is rendered operative andinoperative, a heater tube containing a column of oil in which theheating unit is immersed and by which oil heat is imparted to asurrounding liquid medium, and a control tube containing the controlmeans, being located medially of the heater tube and extending laterallytherefrom, said control tube being in communication with the heater tubeand containing some of the oil, which oil remains relatively cool,regardless of the heat of the oil column, until the zone of the heatedmedium reaches the control tube whereupon the temperature of the oil inthe control tube and the surrounding medium rises together to a point atwhich the control means is set for operation.

6. A heater comprising a liquid storage tank, a heater tube suspendedinto the tank, a control tube in communication with a branch medially ofthe heater tube, an electrical heating unit situated in the heater tube,,a thermostat situated in the control tube, anda volume of oil in theheater tube at a level above the orifice of the control tube, acting todisperse heat to a liquid medium when the tank is filled for an ultimateoperation of the thermostat when the heated zone reaches the controltube, and acting to immediately heat the oil in the control tube for animmediate operation of the thermostat should'the'tank be devoid ofliquid.

7. A heater comprising a heating unit, control means by which theheating unit is controlled so that it is rendered operative andinoperative, and means which at once transmits heat from said unit to asurrounding liquid medium, but of which a portion is dependent upon anincrease in the temperature of said medium up to a determined point forthe action of said control means to render the heating unitinoperative.

8. A heater comprising a tank, a heater tube suspended in the tank,containing a quantity of, oil and having a control tube communicatingwith the heater tube at a point below the oil level and extending to apoint outside of the tank, a thermostat introduced into the control tubeat the latter point, said thermostat having an associated electricalcircuit, and an electrical heating unit embraced by the circuit beingsuspended within the heater tube and immersed in the oil. I

Signed at the city of Washington, in the BARNETT W. MACY.

